Core C The Developmental Neurobiology Imaging and Tissue Processing Core (Core C) provides state-of-the-art equipment and technical support for experimental projects on the assembly and modulation of synaptic, neuronal, and glial structure and function. By sharing technical expertise, equipment, facilities, and professional staff, the Core facilitates cost-effective, cross-project collaborations. The Developmental Neurobiology Imaging and Tissue Processing Core performs cytological and histological processing of experimental tissues, and performs image analysis in a regular and reliable fashion for the developmental synaptic neurobiology, neuroimmunoendocrinology and infectious disease, and molecular biological and genetic studies projects outlined in the MRRC. In particular, the Developmental Neurobiology Imaging and Tissue Processing Core provides a facility for cell and tissue processing and quantitative image analysis at the light, confocal, and electron microscopic levels for many projects comprising the MRRC portfolio. In this regard, the Imaging Core contributes to an interrelationship and synergism among the component projects, resulting in greater scientific productivity and improved cost effectiveness than individual projects could achieve separately. The currently re-configured Neurobiology Tissue Processing and Imaging Core is the result of a merger of two previously existing cores (developmental neurobiology and tissue processing AND combined LSCM imaging and electrophysiology) that had two clearly delineated objectives from the original P30. For many investigators, these two objectives are sequential and therefore have led to a sequential use of two non-overlapping facilities. Now, these tasks are integrated allowing an investigator to accomplish cell or tissue processing and various imaging modalities including: time-lapse live imaging for stable, long-term high-resolution morphological studies; simultaneous real time two photon laser scanning confocal microscopy imaging and recording of plasma membrane potential by the whole-cell patch-clamp technique; monitoring of presynaptic release probability of individual synapses by the de-staining rate of the FM fluorescent dyes; high resolution electron microscopy including serial section analysis of reconstructed cells; and combined immunohistochemical staining and electron microscopy for subcellular localization of epitopes a single unit. These techniques require constantly evolving skills on the side of the investigators and a significant investment in instrumentation.